Add hotkeys to Letterboxd's film detail page, like W for toggle watchlist

letterboxd-film-hotkeys.user.js

// ==UserScript==
// @name         Letterboxd Search Hotkey
// @namespace    hjdarnel
// @version      0.0.3
// @description  Press / anywhere on Letterboxd to search, W to toggle watchlist status
// @author       Henry Darnell https://github.com/hjdarnel
// @include      /^https:\/\/letterboxd\.com\/film\/[^\/]+\/$/
// @downloadURL  https://gist.github.com/hjdarnel/a4d5f24dc7917dc85a407a24386c99b1/raw/letterboxd-film-hotkeys.user.js
// @updateURL    https://gist.github.com/hjdarnel/a4d5f24dc7917dc85a407a24386c99b1/raw/letterboxd-film-hotkeys.user.js
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==

"use strict";

const sleep = (ms) => new Promise((res) => setTimeout(res, ms));

document.addEventListener("keyup", async (event) => {
  switch (event.code) {
    case "KeyW": {
      const removeEl = document.querySelector("a.remove-from-watchlist");
      const addEl = document.querySelector("a.add-to-watchlist");

      if (removeEl && !removeEl.parentElement.classList.contains("hidden")) {
        removeEl.click();
      } else if (addEl && !addEl.parentElement.classList.contains("hidden")) {
        addEl.click();
      }
      break;
    }
  }
});